Cross-Site Scripting (XSS) is an injection attack where malicious scripts are injected into otherwise trustworthy and benign websites. When an attacker sends malicious code, usually as a browser-side script, to another end user through a web application, that is called an XSS attack. Web applications that do not validate or encrypt user input are vulnerable to these attacks because various flaws are widespread.
A malicious script can be sent to an unsuspecting user through XSS to access their data. However, in the case of a hand that should not be trusted, the end user’s browser can’t tell that, and it will execute the script anyway. Essentially, the malicious script is capable of accessing cookies, session tokens, or other sensitive information that the browser can obtain because it believes that the hand is coming from a trusted source.
Don’t users have to deal with cross-site scripting?
Occasionally, cross-site scripting is used to deface a website rather than directly target a user in cases where the attacker aims to impair a website from within. By injecting scripts into a website, an attacker can modify the website’s content or even redirect the browser to another web page, for instance, one infected with malicious code, to change the website content.
How Cross-site Scripting Works?
The vulnerable website needs to be capable of directly incorporating user input into its pages for step one to be possible. It would then be possible for an attacker to insert a malicious string into a web page, which would be interpreted as source code by the victim’s browser when it sees the page.
What are the types of XSS attacks?
XSS attacks can be classified into 3 main types. The following are some of them:
- Reflected XSS: It is reflected in XSS to the extent that the malicious script comes from the current HTTP request.
- Stored XSS: A stored XSS in which the malicious script is located in a website’s database.
- DOM-based XSS: An XSS based on DOM data, in which the vulnerability exists on the client’s rather than on the server’s side, is known as DOM-based XSS.
How to Prevent XSS?
You should ensure that your input is sanitized to avoid XSS attacks. For example, ensure you do not pass data you receive from the browser directly to your application code without checking for errors before doing so. On the Seahawk Media website, there are more such topics discussed that may be of interest.